Reply to "Spicer half shafts"

Dunno what cross-references Pantera U-joints to stock half-shafts, but the vendors do. They did their homework, found something that fits and deserve a little profit from their labors. I buy mine from them.
Diagnosing a sound by long-distance is almost impossible. A 'clicking noise' could come from 3 or 4 places back there, First, look closely at the end-caps of the u-joints- the easy ones inboard and the ones inside the wheelwells where you may need to pull the rear wheels. If theres a shiny polished area underneath the snap-ring that holds the joints together, that joint needs very rapid replacement. Red dust around the cross is also a sure sign of failure.
Second, stock outer stub-axles were undersized from the factory such that the very hard wheel bearing races fret and wear the softer axle surfaces- I've seen grooves 1/4" deep worn in axles.... and they're hollow! This can easily be checked by having a friend throw his haunch into the rear fender while you look closely at the half-shaft. If the halfshaft bows upward, the axle or wheel bearings (or both!) are bad. If not, the shaft will telescope a little.
Third, the lowerr pivot of the axle carrier has a long shft that forms the connection for the lower a-arm. Inside the ca\rrier are two small, thin bushings that likely have NEVER been greased. If one/both are worn, the lower shaft can move around, somtimes making a sound.
Finally, the rubber lower shock bushings often collapse from the wt of the car & age. This allows the bottom of the shock body to touch the triangular welded mount under load, sometimes making a sound.
Other things look for the exhaust touching anything else under load. Or, the sound may not even be coming from the rear- sound travels long distances under a car. Good luck.